Compressor



Nav. 15, T927.- 1,649,299

A. D. FERGUSON Nov. T927. 1,649,299

A D.l FERGUSON COMPRESSOR Filed Aug. 11. 1922 2 Sheets-Sheet 2 H/ n aPatented Nov. 15, 1927.

UNiTEo STATES PATENT OFFICE.

ALEXANDER D; FERGUSON, OF CHIGAGO, ILLINOIS, ASSIGNOB T SULLIVAN MACHIN-N EBY COMPANY, A CORPORATION OF MASSACH'USETTS.

l. Y coiiirnnsson.

Application led August 11 1922. Serial No. 581,253.

My invention relates to compressors, and more particularly to compressorsystems provided with means `for effecting the progressive unloadinthereof whereby with a` constant speed drive it may be possible for thecompressoroutput to be varied in such manner as to `riaintainthedischarge line l pressure within certain desired limits.

the unloading means An object of my invention is to provide an improvedcompressor mechanism. Another object. o my invention is to providean'improved compressor mechanism havingv improved partial or step by stepunloading means. A further object of my invention is to provide animproved compressor system having improved means for effecting a step bystepunloading of the entire system 'in whi h less of complication isinvolved than inr such systemspof other types. Other ob- 'ects andadvantagesof my invention will ereinafter more fully appear.

In the accompanying drawings -l haveshown for purposes of illustrationVone form which my invention may assume in prac-v In these drawings,-

Fig. 1 is va diagrammatic view of av compressor system provided with theillustrative form` of my invention.

Fig. 2 is a view in central vertical section through the intakeunloading means provided for use on the low pressure cylinders of thecompressor units, certainlpartsl being shown in elevation.

Fig. 3 is a central vertical section through the pilot mechanismcontrolling. the operation of my improved system.

Fig. 4J is an, elevation of the saine viewed from a diierent angle.

Fig. 5 is a' transverse section on the line 5-5 of Fig.'3.

Fig. 6 is a detail sectional viewl throughl for one endl of one of thehigh pressure cylinders.

In the form of my invention shown for purposes of illustration in theaccompanyv ing drawings I have shown it embodied in a twin anglecompound compressor system which comprises a pair of angle compounddischarging compressors 1 and 2, each having low pressure cylinders 3and high'pressure cylin, ders 4, the low pressure cilinders beinsupplied with air lfrom inta e lines 5 an through intercoolers 6 toV thegressive or step by step high pressure cylinders 4 which, in turn,discharge by way of a discharge line 7 to a receiver or other'point ofstorage or use.

In the customary construction the compressors 1 and 2 are driven romllacommon crank shaft 7 more intelligible but in order to permit thedisclosure of the piping system employed,.I have shown the compresserunits 1 and 2 set .one behind the other instead of in their customaryrelation. As each of the units is the same in itsgeneral details and asit is by the particular nature of the piping connections lwith the pilotmechanism that the prounloading of the system is accomplished, it will"sutlice if I describe the operative unloading mechanism or onecompressor and then describe the control connections and pilot valve forboth units. i. L

Accordingly2 consideringy thel compressor unit 1 and noting particularlyFig. 2, it will be observedthat the intake line 5 communicates with a.casing 8 transversely of which there extend partition members 9 and 10,the partition members 9 and 10 being connected at about the longitudinalcenter of the casing 8 by a vertical partition 11 so that separate 13are formed and thesechambers 12 and 13 communicate respective-- chambers12 and by circular ports 15 and 16, which ports are surrounded by valveseats 17 and 18, the ports being identical at each side of the partition11 and the upper ports being somewhat larger than the vlower to permitthe insertion of the'valve mechanism. Slidable through the openings V15and 16 are valve members which for purposes 'of convenience will 'bedesignated 20 for the .rear end of the cylinder and 21 for the front endthereof, these valve members each comprising a. pair of circular valveseat portions 22 and 23 which are respectively adapted to seat upon theseats 17 and 18 and from each of the valve seating portions 22 and 23there depend supported by suitable ribs 24 and 25 guiding portions 26and 27 which serve to maintain the esY ported through the valveseatymember 52 and so control the discharge of pressure to'la passage59which communicates with the dis-.

valves 20 and 21 properly centered within their seats duringreciprocation thereof. The valves are hollow throughout their length asindicated at 28,' thereby permitting the connection of the chamber 14with the chamber below the partition 9. Extending ccntrally through thevalve members are valve stems 30 which are connected as at 31 to crossarms 32, these latter being in turn connected by springs 33 with crossarms 34 arranged at the top of operating cylinders 35 which are mountedas indicated at 36 upon heads 37 closing the top of the casing 8. Withinthe cylinders 35 there are pistons 38 reciprocable, these pistonsengaging stems 39 connected with the stems 30 and being operative toforce the valves 20 or 21, as the case may be, closed on admission ofair to their cylinder 35. Suitable stops 42 limit the upward travel ofthe pistons 38.

For the purpose of greater convenience in subsequent reference to theunloading system as a whole, the unloading mechanism for the front endof the low pressure cylinder of unit No. 1 will be designated generally43, that for the rear end thereof 44, that for the front end of the Alowpressure cylinder of the unit No. 2 45, and that for its rear end 46.

It will be obvious that' any suitable type of inlet or discharge valvesmay be employed upon the low pressure cylinders, the mode of operationof my mechanism being absolutel independent of the nature of the valvesuse On the high pressure cylinders I prefer for reasons which willshortly be apparent to employ a type of combined inlet-and dischargemechanism which is disclosed in the application of one Frank A. Halleck,Serial No. 532,741, tiled Jan. 30, 1922, this mechanism comprising apair valve seat elements 51 and 52 coaxially arranged with respect toeach other and disposed at opposite sides of a port 53 communicatingwith the end ofthe cylinder bore whereby an annular chamber 54communieating with the. cylinder bore of the high pressure cylinder isformed between the valve seat members 51 and 52. Suitable annular valves55 normallyl held closed by transversely flexedspring's 56, which aresupby guards' 57, close the ports `58 charge line 7'.l Suitable valves60 normally vheld closed by transversely y lexed springs '-61-vsupported v by a. gna-rd member V62, 'normally maintain passages 63communicating wit vthe intake lchambers 64 of the high pressure cylinderclosed. It will be evident that durf ingthe normal operationof thecompressor,

vupon-the suction strokes of thehigh pressure piston, the valve Willbeunseated' by,

intercooler pressure during I the suction of spaced strokes, and thatduring the discharge strokes the valves 55 will be unseated by thepressure .within the cylinder. One or more of these valve mechanisms maybe used at each end of the high pressure cylinders of both the units 1and 2. Disposed within the intake chambers 64 at thel upper ends of thehigh pressure cylinders 4 of units 1 and 2, there are mechanismsincluding valve seat members bolted as at 66 in position upon the topsof the inlet valve cages 51 and each having a port 67 traversing thesame, which port is surrounded by a valve seat 68. These mechanisms alsoeach include a` valve member 69 adapted to seat upon the valve seat 68and formed at the lower end of a piston member 70 which is reciprocablein a cylinder 71 supported on a closure member 72 and projecting throughan opening in the upper end of the cylinder head of the cylinder 4. Thepiston 70 is normally held in raised position with the valve member 69spaced from the seat 68 by a relatively heavy spring 74 which engagesthe lower side of the head ofv and the inlet valve shut oil` from allcommunication with the intercooler while without pressure in the line 75the valve 69 will stand open and the inlet valve will be free to admitcharges of air from the intercooler. To permit the escape of fluid fromabove the piston 70 any suitable leakage means may be provided, as forexample a pin hole 76. These mechanisms or'the units 1 and 2 arerespectively designated 81 and 82. Each of the high pressure cylinders 4is alsoin addition provided with automatic means, herein numbered 85, ofthe type shown in the patent to H. C. Johansen 1,404,176, Jan. 17, 1922,which is operative to permit the automatic discharge, when thecompressor is completely unloaded, of any small leakage past the intakeclosure valves directly to the tmosphere from the high, pressurecyliners.

.For the purpose of controlling the supply of operating fluid to thereceiver pressure operated unloading 'means 43, 44, 45, 46, 81

vand 82, I have devised an improved pilot valve mechanism which I shallnow proceed to describe. This pilot valve mechanism --1s generallyvdesignated and ,y comprises aspectivelylh 102, 103 and 104, which valvemembers' are controlled by means which l `shall now more specificallydescribe. The

lllU

valve members 101 to 104 respectively are arranged to cooperate with.seats 105,' 106, 107, and 108, the several seats being plane and eachcontaining an'annular groove 109, the several annular grooves 109communicating respectively by passages respectively numbered 110, 111,112, and 113 with pipes 114, 115, 116 and 117, which pipes I willshortly referto again. Each of the seats to 108 inclusive is traversedby a central passageway, these passageways being of uniform diameter andbeing indicated at 118. Extending longitudinally through the severalpassageways mentioned is a stem 120 formed at its top with a plunger orpiston 121 upon which a spring 122 housed in the vcasing 123 andadjustable by means of a follower 124 coacts. Formed upon the stem 120is a collar 125^which is adapted to engage after a predeterminedmovement from a given lower position which will be more fully describedlater, the valve member 101 and lift it from its seat 105. Resting uponthe top of the valve member 101 is a sleeve 126 which is of slightlyless length than the distance between the valve member 101 and the valvemember 102 when both are seated. This sleeve is adapted to be raised onupward movement of the valve 101 and after suicient upward movement toengage and lift the valve member 102. A similar sleeve cooperating withthe valve 103 in a similar manner and 'designated 127 is superimposed onthe valve 102 and a1 further similar sleeve 128 is arranged to be litedby the valve member 103 and to raise the valve member f 104. The piston121 is slidable in a cylinder 129 Jformed in the casing 123 and fluidpressure from a suitable source. is conducted by a passage 130 tochambers 131, 132, 133, and 134 in which the valve members 101 to 104respectively are located. This pressure normally tends, of course, tomaintain the several valve members seated and as it will be observedthat each of the valve Y'members is raised successively alone from itsseat and as it will be observed that the valve members are allotsubstantially equal diameter with the piston 1 1, it willV be apparentthat the pressure of air acting beneath the piston 121 is such as to/practically neutralize the work d necessary in raising one of the valvemembers 0E its seat. The stem 120 asses through a suitable bore 136downward into a s ace formed between a pair of support mem ers 137formed integral with a support 138. Secured to the support 138 is anexpansible diaphragm chamber 139 to whose interior 140 Huid may beconducted by a passage 141 and a series of grooves 142 formed ina-member 143 which threadedly 'engages the lower head 144 of thediaphragm chamber and l holds-it tixedly in position on the member 138.The member 143 istraversed by a passage 145 through which a plunger 146,alined with'the stem-120 and having suitable sealing grooves 147 snuglyextends, the plunger 146 engaging at 148 the upper-'head 149 ofthediaphragmchamber. The plunger 146 is provided at its lower end with ahandle 150 and is traversed by a series of four parallel transversepassageways 151, ,152, 153,

` and 154. The member 143 is provided with seated and as each successivepair of holes is brought into register an additional valve is opened.The function of this mechanism will shortly be explained.

Leading from a receiver pressors discharge, or from their commondischarge line, is a passage or connection controlled by a stop valve161 and provided with a strainer 162 to prevent the passage ofimpuritiesor solid matter to the valve mechanism. Beyond the strainer 162 is a T163 from which a connection 164 leadsto the passageway 130 previouslydescribed. From -the other end of the T a connection 165 leads to thepop valve 166 which pop valve. works on the principle of the ordinarysafety valve, that is, it opens when a desired pressure is reached inthe line 160' and permitsy a pressure equal to the excess the desiredpressure in line 160 to pass 4through the valve before it again closes.

The chamber above the valve in the pop valve 166 communicates with thepassage 1'41 so that a pressure equal to the excess above the seating ofthe pop valve will be transmitted to the diaphragm chamber 140. Upon thetop of the pop valve 166 is a safety valve 167 loaded to preventbuilding up of' more than a desired ressure in the diaphragm chamber140. hole leak or adjustable leak 166 as may be desired' is arranged atany suitable point between the pop valve 166 and the 'limits of thediaphragm chamber whereby the pressure in the chamber 140 will promptlyfall' on closure of the pop valve 166; Leakage may also to which thecombe permitted aroundthe plunger" lill) above lll) suitable pin.

146,41. shoulder 168 thereon then cooperat-,

ing with the top of the member 143 in preventing leakage whenthediaphragm is collapsed to its smallest size. j

It will be recalled that a seriesA of pipes 114, 115, 116, and 117 havebeen described above; These pipes are connected to the several unloadingmeans 43, 44, 45, 46, 81 and`vv 82 as follows: The pipe 114 connects by.

branches 17.5 and 176 respectively to the low, pressure intake closuretyp-e unloading means 44 and the high pressure unloading means 81 ofunit No. 1, the pipe 115 connects vto the vother low pressure unloadingmeans 43 of vunit No. 1. Pipe 116 connects -by suitable branches 177 and178 respectively to the low pressure unloading means 46 and the highpressure unloading means 82 of unit No. 2, while the passage 117connects to the second'low pressure'unloading means 45 of unit No. 2.

` From the description of the mechanism itself, the mode of operation ofthis invention will already be apparent,'but it may be brieflysummarized as follows: Let. it be assumed that the compressor issupplying air to a plant in which the demand for air is such as to causethe compressor to operate at full load to maintain the necessary supplyline pressure'. .Now let it be assumed that the demand for air falls offslightly. As a result, since the compressor is being driven at aconstant speed, the pressure in the compressor discharge line, i. e. thesupply line tothe plant, will rise and as aD result the pop valve 166which is set to open when the pressure exceeds the desired line/pres#su-re, say 100 pounds, will open and pressure will be transmitted intothe diaphragm chamber 140. 'If the pressure rises to a value say two orthree pounds in excess of the desired 100 pounds, `the expansion of thediaphragm chamber will cause the collar 125 t\o raise the valve 101 andpressure will be supplied to the line 114. As a result, air will besupplied to close the intake to the head end ofthe low pressure cylinderand to the head end of the high pressure cylinder, this beingaccomplished by means of the unloading mechanisms 44 and 81, andthe-compressor system will then operate at three-quarter load, unit No.2 continuing to'operate at full load and unit No. 1 acting as acompressor havin@ single acting high and low pressure .cylin ers. It thedemand for air fallsv off sufficiently to cause the pressure to reach avalue a few pounds higher than was necessary to open valve 101, valve102 will be raised by continued up- Ward movement of valve 101, causingthe sleeve 118 to lift valve 102. Pressure will then be transmittedthrough pipe 115 to' unloading means 43and the intake to the crank endof low pressure cylinder ofunit No. 1 will also be closed. Unit No. 1will then be completely unloaded since no air except a small yquantitywhich may leak in can secure admission to the compressor. The smallquantity of air which may leak past the `closed intake controllingvalves 20 and 21 orwhich may leak in through the packings around thepiston rods, etc., will be discharged direct to the atmosphere by theautomatic means 85 previously described. If the pressure in thedischarge line rises still further, the valve 103 will be opened andpressure supplied through pipe 116 to close the connections between thehead ends of the low and high pressure cylinders of unit No. 2 and thepoints of suction of these cylinders, that is, the low pressure cylindercan no longer draw in air from the atmosphere and the high pressurecylinder canno longer draw in air from the intercooler, as to their headends respectively. It the demand falls oil' still further or ceasesentirely, the valve 104 will finally be opened and transmission ofpressure through line 117 to the unloading means 45 will completelyunload unit No. 2. As the demand for air increases, the compressor unitswill be progressively reloaded l in an obvious manner as the valves 104,103,

102, and 101 are successively closed.

In case the demand for air over a long period is less than the capacityof the com pressor, the handle 150 may be forced upward and by theinsertion of a suitable pin through the holes 151 and 159 thecompressors maximum output may be reduced to three-quarters of itspotential output, or byinserting the pin in other pairs of mating holes,other still smaller maximum capacities may be obtained. y vWhile I havein this application specilical-` ly described one form which myinvention may assume in practice, it will be understood that this formof the same is shown for purposes of yillustration and that theinvention may be modified and embodied in other forms without departingfrom its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters -Patent is:

1. In a pumping unit, in combination, a compound pump havingdoubleacting high and low pressure cylinders each provided with suitable inletand discharge valves, means for closing olf communication between theinlet valves atv one end of both the high and .low pressure cylindersand their respective supply spaces,l means for closing the V...intake tothe other end of said lowpressure cylinder, pump discharge pressurecontrolled means controlling said first and second mentioned means, andrelief valve means for venting said high pressure cylinder.

2. In a pumping system, a pair of compound pumps each )having doubleacting.

high and low pressure cylinders which are provided with suitable inletand discharge valves, means for unloading said pumps comprising intakeclosure means for one end of both the high and the low pressurecylinders of one of said pumps, intake closure means for the other endof the low pressure cylinder of said pump, similar unloading means forthe secondl pump, pump discharge pressure controlled means forcontrolling serially i ally disposed inlet and of said pumps.

said several unloading means, and automatic relief means for the highpressure c linders 3. In a compressor, in combination, an inlet valve, ayalveseat therefor, and 1ntake closure means including a valve coaxlallyarranged with respect thereto and movable rectilinearly axially thereof,and a valve seat cooperating with said second valve, said seat beingdisposed parallel to said first seat.`

4. In a compressor, in combination, coaxidischarge valves, and intakeclosure means coaxially arranged with respect thereto.

5. In a compressor,

with adapted to control flow' of fluid to said inlet valve, and acylinder and piston coaxially arranged with respect to said valves foroperating said intake closure valve.

6. In combination with coaxially arranged inlet and discharge valvemechanism for a high pressure cylinder having a head, of intake closuremeans coaxially arranged With espdect to said inlet valveV disposed insaid ea v 7. In a compressor, 1n combination, an iniet valve, a cagetherefor, and a -cover fork controlling How of fluid through said cage,and actuating means through which said controlis effected including acylinder and piston coaxially arranged with respect to said inlet valve.

8. In combination with a compressor inlet and exhaust valve mechanism,of intake closure means coaxially arranged with respect thereto, andactuating means therefor, said closure means constituting an element ofsaid actuating means.

9. In a compressor system including a plurality of pumping unitscooperating in delivering air to a common control means for controllingthe latter operative to cause successive unloading of said units andincluding means for manually shutting down certain of said units.

10. In a compressor system vincluding a plurality of pumping unitscooperating i'n delivering air to a common discharge line, unloadingmeans for each unit, and common control means for controlling the latteroper- ,A

ative to cause successive unloadingof said umts and including meansfor,1 manually shuttlng down certain of said units, While leaving the.remaining .units under the autop operable matic control ofsaid-controlling means.

11. -In a pumping mechanism, a plurality of pumpin units, commoncontrolling lmeanstherefor adapted to control said units seriallyautomatically, and manually operable means adjustable to remove certainof said units from automatic 12. In a pumpingmechanlsm,

in combination, an inlet valve, avalve disposed coaxlally theredischargeline, unloading means for each unit, and common control While ,leavingthe remainder subject thereto.

` a plurality I of lpumping units, common vcontrolling means thereforadapted to control said units serially automatically,'and manuallyloperable means adjustable to remove certain of said units vfromautomatic control While leaving the remainder subject thereto and underidentical controlling conditions.

13. In a pumping mechanism, a plurality ofy pumping units, commonvcontrolling means therefor adapted to interrupt the pumping operation ofsaid units at different predetermined pressures, and manually operablemeans adjustable to remove certain of said .units from automatic controlWhile leaving the remainder subject thereto.

14. In a pumping mechanism, a-plurality of4 pumping units, commoncontrolling means therefor adapted' to interrupt the pumping operationof said units at different predetermined pressures, and manuallyoperable means adjustable to remove certain of said units from automaticcontrol While leaving the remainder subject thereto at the same pressureconditions as when all are automatically controlled.

15. In a pumping mechanism, of pumping units, common means thereforadapted to control said units serially automatically, and manuallyoperable means adapted to act upon the automatic means and adjustable toremove certainof said units from automatic control whileleaving theremainder subject thereto.

16. In a 'pumping mechanism, a plurality of pumping units, commoncontrolling means therefor adapted to control said units serially ablemeans adapted to act ,upon the automatic means and adjustable to removece1;- tain of said units from automatic control While leaving theremainder subject thereto and under identical controlling conditions.17. In a pumping mechanism, a plurality common controlling to interruptAthe a plurality of pumping units, means therefor adapted .pumpingoperation of said units at different and 'manually predeterminedpressures,

to act upon the operable means adapted automatic means and adjustable toremove certain of said units from automatic control while leaving theremaindery subject thereto.

A18. In a pumping mechanism, a plurality of pumping units, commoncontrolling means therefor "adapted to interrupt the pumping operationof said units at different redetermined pressures, and manuallyautomatic 'certain of said;l units from automatic control While leavingthe remainder subject-thereto at the same pressure" conditions as whenall are automatically controlled.

In testimony whereof I aiiix'mysignature.

ALEXANDER D. FERGUSON.

automatically, and manually opercontrolling means adapted to act Luponthe means vand adjustable to remove-

